Liquid-feed system and method



C. L. STOKES.

L|QU!D FEED SYSTEM AND METHOD.

I APPLICATION FILED JAN-9.1918- RENEWED FEB. 11,1922. 1,430,038.

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C. L. STOKES.

LIQUIDFEED SYSTEM AND METHOD. APPLICATION FILED JAN-9.1918. RENEWED FEB. 11.1922- Patented Sept. 2 6, 1922,

v M K 2 SHEETSSHEET 2.

.tems and particularly Patented Sept. 26, 1922.

PATENT OFFICE.

CHARLES LAWRENCE STOKES, 015 L08 ANGELES, CALIFORNIA LIQUID-FEED sYs'rEni AND METHOD.

Application filed January 9, 1918, Serial No. 210,965.

To (ZZZ-20110111 it may concern:

Be it known that I, CHARLES ,LAWRENCE S'ronns, a citizen of the United States, and resident of Los Los Angeles and State of California, have invented certain new and useful Improve,- ments in Liquid-Feed of which the following is a specification.

This invention relates to liquid teed sys to liquid teed systems operated by the vacuum induced by the suction strokes of an internal combustion engine.

It includes a method in conjunction with an apparatus and includes as one of its principal features a high level service reservoir consisting of a single chamber. The vacuum is applied to this chamber to suck the liquid from a low level supply tank as for instance the tank usually carried on the rear end of an automobile and from this chamber the liquid flows by gravity directly to the consumptiondevice, for instance, the car bureter of the engine.

The application of the pumping vacuum is intermittent and is controlled by a float within the reservoir which operates 'to destroy the vacuum and discontinue the pumping when the liquid reaches a predetermined high level and which restores the vacuum when the liquidtalls to a predetermined low level. Ordinarily these periods of pumping and discharging follow each other rapidly enough to maintain a supply of the liquid to. the ca'rbureter constant enough for all practical purposes. Nevertheless; under certain practically unavoidable conditions as where the automobile is laboring up a steep grade with open throttle and decreasing speed, the vacuum induced by the suction strokes of the motor becomes too weak to lift the gasoline from therear tank tothe reservoir so the reservoir does not fill, the float'docs not rise, the vacuum is not cut off and so even though there be a considerable supply of liquid in the reservoir, thevacuum prevents its gravity fiowto the carbureter. In practice, the engine stops be fore the vacuum gets low enough to permit any flow to the carbureter. Hence, it is now the universal practice to make the high level reservoir for such purposes a twochamber receptacle, one serving as the pump chamber and the other a dump chamber into which the pump chamber empties by gravity thereby maintaining a. supply of liquid at Angeles, in the county of' Systems and Methods,

Renewed February 11, 1922. Serial No. 535,926.

all times free to flow carbureter.

By In present invention, I am able to employ a liiigh level reservoir having only a single chamber which serves as the vacuum pumping chamber iLIIdlSO arrange matters so that all of theliquid therein may be, available as a reserve supply during the above described periods when the available suction is notStlOng enough to pump and when the reservoir is not full enough to operate the suction cut-ofi'.

To this end I dispense with the customary dump chamber and connect directly to the reservoir both the drop pipe from the reservoir to the carbureter and the lift pipe from the tank to the reservoir, so that the drop pipe contains a solid column of the liquid and I predetermine the height .of that column so that its hydrostatic suction on the reservoir shall have a value predetermined with reference to the above described low pumpin vacuums commonly occurring in practica use of the automobile so that the solid column of liquid inthe drop pipe will be heavy enough to draw down the liquid from the high level reservoir against the opposing suction of'such low vacuums. For instance, if I locate the reservoir ten inches above the carbureter eliminating the dump tank and maintain a solid column of liquid in the drop pipe, the weight of said column will draw down liquid from the reservoir when ever, there is less than a ten inch vacuum in the reservoir. This expedient alone, however, would be entirely ineffective in practice since the rear tankis normally lower than the carbureter, say ten inches, and the lowest vacuum that will suck trom the rear tank to the reservoir is this ten inches plus the ten inches that the reservoir is above the carbureter Hence, the reservoir will not pump on less than a; twenty inch vacuum. This leaves a practically prohibitive gap between the twenty inch vacuum that will pump liquid up from the rear tank and the ten inch vacuum which can be overcome by the solid column of liquid in the drop )1 e.

1 This gap I have succeeded in bridging for all'practical purposes by making the weight or hydrostatic head of the column of liquid in the lift pipe between tank and reservoir abnormally light by utilizing the air litt principle disclosed in my prior patents of June 19th, 1917, Nos. 1,230,537,

by gravity to the 1,230,596 and 1,230,832. In this way the sucked-up fluid is made to consist partly of air which has no weight. In this way. the total effective weight of the composite fluid lift column can be decreased to, say twothirds or one-half or even one-quarter the weight of a solid column of gasoline of the same height. Thus. the twenty inch lift column of gasoline and air may be made lighter than the ten inch discharge column of gasoline without air. Or more generally stated. the gap between vacuums that will pump the lift column and vacuums that the discharge column will vercome and draw against. may be decreased as much as necessary to make the supply obtainable by the latter method continuous with the supplyobtainable by normal operation, or as nearly so as may be found practically necessary in anv given case.

it is entirely practical and in many cases desirable to make the height of the reservoir above the carbureter float chamber and the amount of air admitted into the lift line great enough so that the down column will be heavy enough to draw gasoline from the reservoir by gravity while the suction in the reservoir is still great enough to suck the air and liquid from the low level tank. In actual practice. the vacuums suitable for such simultaneous pumping and discharge for a single chamber are likely to be transitory. because the road grades and motor speeds vary widely and rapidly. but the ability to secure an overlap' of these conditions is of very great importance because it makes it possible to design any given installation so that the entire contents of the pumping chamber will be available as an emergency reserve to carry over the above described critical condition of operation. where all vacuum feed systems on automobiles have been found to be weakest.

My invention includes various novel features of the apparatus some of which particularly :adapt it for the special purposes above described and all of which are useful in various other forms of vacuum feed apparatus. Among these features may be mentioned arranging the drop pipe and its connections to the reservoir so that the column of liquid therein isat all times in free communication with the body of liquid within the reservoir; arranging the check valve at a low level point of such column, preferably below the level of liquid in the carbureter float chamber; employing a substantially neutral check valve. that is one. which opens and closes in response to forward or reverse flow of liquid as distinuished from one which is made self-closing y gravity or spring pressure; utilizing the reservoir inlet pipe as a guide for the float in the reservoir; providing such float with a shield or bafile adapted to deflect the incoming liquid away from the entrance to the suction pipe; providing a simplified form of quick-throw or kick-spring for rendering the suction controlling function of the float more definite. instantaneous and certain.

The above and other features of my invention will be more fully understood from the following description thereof in connection with the accompanying drawings in which Figure 1 is a side elevation showing the various parts of the apparatus and indicating certain significant features of their location and relative arrangement;

Figure 2 is a vertical section showing the pumping and the reservoir operating mechanism therein:

Figure 3 is a section on the line 3-3. Fig ure 2;

Figure 4 is a section on the line l-'l.'Figure 2;

Figure 5 is a section on the line Figure 2;

Figure 6 is a longitudinal sectional view of the valve 9, Figure 1;

Figure 7 is a vertical longitudinal section of the carbureter of Figure 1 and Figure 8 is a similar view of a modifita tion.

By reference to Figure 1 it will be seen that the system comprises a low level tank 1. which may be the gasoline supply tank carried on the rear end of an automobile. It is provided with a filler cap 19 in which is an air vent 20. A lift pipe 2 having an inlet for liquid and alsoinlets 21. 22 at different levels extend upwardly and horizontally to the high level service reservoir and vacuum pumping chamber 3. This chamber communicates through valve casing 4 and pipe 5 with the intake manifold 6 of an internal combustion motor of any known or desired type. The suction. strokes of the engine cause a vacuum in this manifold which varies with the speed of the motor and the adjustment of the throttle valve 7. These variations may be very wide since with light loads the throttle may be nearly closed while the speed of the motor is very high and conversely, with heavy loads. the throttle may be wide open while the speed of the motor may be very slow.

A carbureter having a float feed chamber 8. is located at the intake end of the intake manifold 6 at a level above that of the tank 1 and below that of the service reservoir 3. The flow of liquid fuel and its level within the float chamber. are governed within limits by the float 8' which rises and falls with the level of the liquid and operates through lever 13 pivoted at 14 to open and close the inlet valve 11 secured thereto by a ball and socket connection 12. A vent 10 in the top of the carbureter float chamber communicates with the atmosphere and operates to maintain atmospheric pressure within the float chamber 8 regardless of the changes of level of the liquid therein.- The float chamber operates to maintain an approximately constant le el of liquid ready to be sucked into the car ureter jet 9L1 which is adjustable by needle controlled by thumb-screw 42. The above, or other desired means for carbureting the air and controlling the level of liquid in the float chamber may be employed.

The liquid flows by gravity from the reservoir 3, through pipe 15, valve casing 9 and-pipe 18 .to the. carbureter float valve 11. The valve casing 9 is shown as comprising screw-threaded sections, one communicating with the pipe 15 and the other with the pipe 18. It is located well below the level of the reservoir 3 and preferably below the level of the liquid in the carbureter float chamber 8. The movable valve element consists of a plate 17 adapted to cover the inlet from the pipe 16. This plate is very light and hangs vertically upon the headed guide ins 16, 16, which extend horizontally through and loosely engage perforations in the plate. neutral in the sense that it has no self-closing tendency, yet the slightest reverse flow of the liquid will force the plate backward, and, by reason; of its" loose fit on the pins 17, it instantly and" perfectly adjusts its plane to the plane of the inlet opening thereby making a perfect seal'a'nd preventing all back How of liquid except the slight initial flow which is necessary to seat it.

Since pumping of the gasoline from the low level tank 1 through the lift pipe adepends upon suction applied to the reservoir 3 from the vacuum in the intake manifold 6, the rapidity of pumping as well as the height to which the liquid may be pumped depends upon and varies with the degree of such vacuunr- During'ordinary normal operation,this vacuum is high and while this operates topump up liquid very rapidly through li'ft pipe 2, it also operates to prevent-the liquid from discharging downwardly by gravity through pipe 15.; Hence, itis necessary to provide means for breaking the vacuum and restoring atmospheric pressure within the reservoir 3, whenever the liquid therein has-been pumped to a desired maximum level and to reestablish e level.

the vacuum 'and resume pum-pin whenever the liquid falls below a desire minimum So far as vconcerns the broader features of my invention, any known or desired means suitable for the purpose may be employed, but more specifically consid--' ered in invention includes the novel means shown in the drawings.

By reference to Figure 2 it will be seen that, the connection 4 to suction pipe '5 1s a valve casing formed with a valve seat 37 adapted to be engaged by a valve 36 on Thus arranged, the valve is moved up valve stem 33. The valve has a central longitudinal perforation open to atmospheric pressure at the upper end and communicating with the interior of the reservoir 3 at the lower end. As a means for cutting off thiscommunication I- provide a sliding sleeve 34 which is normally held in a position to close the air inlet by pressure of spring 38 which encircles valve stem 33 and bears against the under side of valve 36.

Any suitable means may be employed for operating these valves to apply the suction and cutoff the air so as to create a pumping vacuum in the reservoirand when a suflicient supply has been pumped to cut off the suction and admit the air. The means shown in'the drawing comprises a radius arm or lever 29 having one end bifurcated and pivoted to the yoke 19. The free end loosely engages the valve stem 33 between the sleeve 34 which is pressed downwardly against it by the spring 38 and a supporting washer 35 held by a cotter pin 43 which'passes through the valve stein.

In Figure 2 the 'freeend of lever 29 is shown in the lowermost position where the air inlet is closed by the sleeve 34 and the valve 36,37 is open.

however, it is obvious that the valve 36 will be forced against its seat 37 thereby cutting off the suction and then further movementof the lever 29 in the same direction will serve to slide the sleeve 34 upward from the air inlet opening thus establishing communication with the atmosphere and relieving the vacuum Within the float is guided upon a vertical downward extension of the inlet pipe 2 and rises and falls with the changes of level of the liquid within the reservoir. The float actuates the lever 29 through the movement of a second radius arm or lever 28 which. like 29, is bifurcated and pivoted to the yoke 19. The movement of the lever 28 is communicated to the lever 29 only through the medium of spring 32 which extends straight across between them. The bifurcations of the two levers and the yoke-form of the pivotal support alfords space for free play of the levers without danger of bring ing the intermediate portions of spring 32 into contact with any of these parts. The free end of the lever 28 engages freely between pins 30 and 31 which are supported by and move with the float 24c.

When the lever 29 is 5 cause the vacuum is high and applying suction speedily fills the tank. This causes the float to rise thereby lifting the free end of lever 29 and applying additional tension to spring 32 until the line of tension passes above the pivotal point of levers and so becomes effective to snap upward the free end of lever 29 thereby lifting the valve at. cutting off the suction. lifting sleeve 34 and admitting the air.

It will be noted that the proportions of the levers 2b and 2S) and the location of the free end of 28 with respect to its pivot are predetermined so that only a very slight fall in the level of the liquid is required to bring the spring 32 below the pivotal point of lever :2) and thereby restart the pumping. This gives a predetermined high level and a predetermined low level which are quite close together and insuresvery short pumping periods when the pumping vacuum is of normal power. As a result, the interior of reservoir tlis normally maintained quite full of the liquid and most of the. time this liquid is at atmospheric pressure and hence perfectly free to flow down through pipe 15 and 'alve 1? whenever the carburetor float chamber valve 11 is opened by its float 8. Hence. in actual practice with normal pumping vacuum. there is never any difficulty in maintaining the required level of the liquid in the float chamber of the carburetor 8.

' Under the less usual but not uncommon condition described above. where the motor is under heavy load and operating at low speed with wide open throttle, the pumping becomes slower and as soon as it becomes too slow to supply the consumption of the liquid fuel in the carbureter the liquid in the reservoir 3 instead of being replenished by the pumping continues to fall notwithstandin the pumping and the float 24 is not lifted ,to cut off the suction and restore at-- mosphere. but remains in the lower position where the supply of liquid in the reservoir 3 is subject to the upward suction of whatever vacuum there is in the. manifold.

l nder these conditions, my invention renders available for down flow through the. pipe 15 to the carburcter the entire contents of the reservoir 3.

As before explained. this involves two expedients. Instead of having the reservoir just enough above the carburetcr float chamber to give a free gravity discharge of the liquid when there. is no vacuum in the reser-. voir, I arrange the reservoir at a considerable height so that the discharge column maintained in the pipe 15. will have sullicient weight, that is suliicient hydrostatic head to draw down liquid from the reser voir while there is yet a considerable vacuum within the reservoir. At. the same time. I arrange for admission of air through air inlet-s 21, sutlicient to considerably decrease the weight, that is the hydrostatic head of the lift column of liquid in the uptake pipe 2.

By varying these two factors to suit the minimum vacuums occurring in practice, I am able to make the conditions of pumping vacuum and discharge vacuum approach each other as nearly as may be necessary to make the emergency supply practically continuous with the normal supply. Moreover, where the conditions are not too unfavorable, as for instance, where the height of the carbureter above the low level tank is not too great, or the amounts of air practically useable in the lift column are not too small. or the minimum pumping vacuums not too low. the conditions of vacuum pumping and gravity discharge may be made to overlap so that pumping and dumping may be simultaneous.

In fact under especially favorable conditions, I have demonstrated that the overlap may be made so great that the discharge by gravity will become available while the pumping vacuum is still sufficient to supply the carbureter demand. Furthermore. under extreme conditions the simultaneous pumping and dumping operation may be made the usual method of operation of the system, in which case the intermittent cut-off and pumping method will become the unusual or emergency method.

In most cases. however, I prefer that reservoir 3 should contain a sufficient quantity of liquid to supply the engine during a low vacuum period oven though the conditions are too unfavorable to permit of anyreplenishment'b'y pumping during that period.

As an illustration of my method of opera tion. we may consider the case where the float has been set to apply the suction and start pumping when the liquid in the reservoir 3 has fallen to the level indicated by the dotted line XX. Figure 1. This level may he, say 12 inches above the dotted line YY, which is assumed to indicate the normal level of liquid in the carbureter float chamber It is obvious that whenever there is less than a 12 inch vacuum in the manifold and reservoir 3, the weight of the solid gasoline column from XX to Y-Y will over-balance the lifting suction in the reservoir and the liquid will flow downward into the 'carburcter float chamber 8, unless prevented by closing of the valve 11. Suppose then that the vertical lift from ZZ. which is supposed to be the level of the liquid in the rear tank, to the top of the lift pipe 2 he, say 20 inches. It then the air admitted into the lift column through the restricted opening 21 equals, say. half the volume of gasoline in the pipe 2. a vacuum of 10 inches will be sufficient to pump liquid up into the reservoir. Consequentlv. whenever the vacuum in the reservoir 3 is greater than 10 inches and less than 12 inches, the corn ditions of pumping and dumping will overlap.

Furthermore, it is entirely practical to make the volume of air in the lift pipe 2 much greater than above indicated and un der certain conditions, the amount of liquid in the lift pipb may be the equivalent of no more than 4 inches or even 3 inches of solid liquid. In such case. the conditions for simultaneous pumping and dumping will. exist whenever the vacuum in the manifold is less than 12 inches and greater than 4: inches.

. Such wide overlap is seldom necessary, and I prefer to make it less. in order that I may have greater latitude in the design and practic-aloperation of particular installations so as to accommodate wide variations in the depth of liquid in the rear tank, the inclination of the car when traveling up steep hills and the practically permissible elevation of the reservoir above the carbureter.

As before, intimated, the actual overlap of the two conditions not always necessary. If the effective weight of the lift column of liquid were 12 inches and the discharge column only 10 inches. there would be neither pumping nor dumping for vacuums between 12 inches and 10 inches, but such condition will not persist long enough for the carbureter float chamber to empty, because changes in grade, or the failing supply of gasoline in the carbureter float chamher, or the operators changing of. the throttle adjustment will change the enginespeed, and any such change will be suflicient to vary the available vacuum much more than the 2 inches necessary to get above or below the non-pumping and non-dumping condition.

I prefer to arrange the outlet for the liquid and air from pipe 2 into the tank, in the form of elongated slot 26 located at or above the normal level of liquid inthe tank. A much more elongated opening 27 is formed in the floatso as to leave 26 unobstructed throughout the range of movement of the float. Above this opening, and mounted 011 the same guide, I provide a coneshaped deflector 25 which tends to prevent particles of liquid from being projected into the vicinity of the suction intake through valve seat 37 Where they might find their way to the manifold and over-carburet the charge passing therethrough into the engine. For the same reason, I prefer to have the valve 36 and intake through valve seat -37 located at the top of an upwardly extending recess, as shown in Figure 2.

In Figure 8, I have shown amodified form of float controlled carbureter inlet valve, the only difference being that in the form shown in Figure 8, the ball and socket oint is modified by cutting the socket deep- -of liquid in said er and correspondingly lengthening the neck of the ball member. Thus constructed. the valve ll is positively closed by the float when the liquid reaches apredetermined high level. and is positively opened again when the liquid reaches a predetermined low level. but for all intermediate levels. the valve will open freely to let liquid flow from the reservoir 3, and will close the carbureter float chamber when the flow reverses. Thus in the arrangement shown in Figure 8, the valve. 11 performs not only the function heretofore described in connection with Figure 7, but also the function described in connection with the valve 17 in casing 9. This makes it possible to dispense with the valve 17 in casing 9.

Having thus described my invention. what strictedly admitting air thereto to lighten the weight of tihe ascending column. a carbureter having a float-controlled inlet valve, a down-flow pipe connecting said reservoir and said inlet and an automatic check valve for preventing reverse flow of fluid in said down flow pipe; the reservoir being positioned at such an elevation above said tank and said carbureter being positioned at such an elevation below said reservoir that the static head of the column of liquid in said down-flow pipe is greater than the weight of the column of mixed air and liquid in said ascension pipe for the purpose de scribed.

2. The combination of a low level liquid fuel tank, a high level. single-chamber feed reservoir. a vacuum connection from said reservoir adapted to be fitted into the induction pipe of an internal combustion engine, an ascension pipe from said tank to said reservoir and having means for restrictedly admittingiair thereto to lighten the weight of the ascending column. a carbureter having a float-controlled inlet. adown-flow pipe connecting said reservoir and said inlet. the reservoir being positioned at such an elevation above said tank and said carhureter being positioned at such an elevation below said reservoir that the static head of the column down-flow pipe is greater than the weight of the column of mixed air and liquid in said ascension pipe. and automatic means for preventing the up-flow of liquid in said down-flow pipe to said single chamber reservoir during intervals of high suction pressure,

3. In a vacuum feed system of the class described, a low level tank, a high level reservoir having only a single chamber, a conduit leading from the low level tank to the reservoir, means for restrictedly admitting air to said conduit at the low level,

- means for applying the suction of the motor to the high level reservoir to maintain a partial vacuum therein and withdraw the air there separated from the liquid, a conduit directly communicating with and leading downward from said reservoir to the carbureter, a check valve in said conduit below the normal level of liquid in the carbureter arranged to prevent reverse flow of the liquid toward the reservoir, the height of the reservoir above the carbureter and the amount of air restrictedly admitted to the lift conduit being predetermined and proportioned so that the static head liquid in the downward column will be greater than the static head of the column of mingled air and liquid in the lift conduit, in combination with float controlled meansin the reservoir for automatically cutting off the vacuum and venting thereservoir when the liquid reaches a predetermined high level in the latter, whereby the apparatus will lift and discharge the liquid alternately at high vacua and simultaneously at low vacua.

l. In an apparatus of the class described, a low level tank, a high level reservoir, an intermediate conduit, means for restrictedly admitting air to said conduit at the low level, means for applying'vacuum to the reservoir at the high level and a terminal discharge pipe for said'conduit extending vertically downward into said reservoir, in combinationwith a float vertically guided upon said discharge pipe, openings carried by said float adapted to register with supplemental discharge openings in said discharge pipe and a downward deflector carried by .said float above said supplemental discharge openings I 5. In a system of the class described, a reservoir, a vacuum connection and valve therefor, a float for intermittently closing and opening said valve in accordance with the level of liquid in the reservoir, in combination with a kick spring device con necting said float and said valve, said kick spring device comprising fixed, aligned, space-apart pivots intermediate the float and the valve, bifurcated radius arms having their bifurcated ends mounted on said spaced pivots and their free ends engaging respectively the float and the valve, and a spring connecting the bifurcations of said radius arms substantially in a vertically central plane at right angles to the axis of said pivots, the-proportion of parts being such that the normal range of movement 1 ,esopae of the float will carry the free end of is radius arm alternately above and-below the dead center of stress of said spring with reference to said fixed pivots, thereby causing snap'opening and closing of said valve.

6. In a system of the class described, a low level tank, a high level reservoir, a carbureter having its float chamber at an intermediate level, a conduit extending from the tank to the reservoir, a second conduit extending from the reservoir to the carbureter float chamber, in combination with an inlet valve in the carbureter float chamber, said valve being formed and arranged to normally close, by gravity against reverse flow of liquid toward the reservoir and having a lost motion connection with'said float, whereby said valve will be positively opened When the float is in the lowermost position, positively closed when the float is in the uppermost position and, for intermediate positions, will operate automatically to permit gravity flow of liquid into the carbureter float chamber and to prevent reverse flow of li uid toward the reservoir.

The method of supplying liquid fuel from a low level tank to a carbureter at a higher level through a continuous conduit extendingfrom said low level upwardfito a point. considerably above said carbureter -level and downward to the latter level by means of the variable vacuum available in the manifold of a variable load, variable speed internal combustion engine, which method consists in applying the variable .vacuum at a high point in said conduit,

restrictedlytadmittingair to said conduit at the low level thereby causing a rising column of mingled air and liquid to flow uppoint; permitting the liquid to settle out from the air at said high point and withdrawing the air by the suction of said vacuum so as to maintain in the descending portion of said conduit a solid column of liquid of less vertical height but heavier than said rising column; whereby at times of certain predetermined low vacua the drop column will withdraw liquid from the higher point simultaneously with the raising of the li hter column. of air and liquid through the 11ft portion of the conduit; and, at times of higher vacua, automatically preventing reverse flow of said liquid from said carbureter to said high point and utilizing increasing level of liquid at the high point to intermittently cut off the vacuum and vent the high point Signed at New York city in the county of New York andEitate of New York this 24th day of August, 191?.

Ci'llAldilQES LAWRENCE STQKES.

ward through said conduit to said high 

